Pyridyl-2-oxyphenyloxime derivatives and their use as herbicides

ABSTRACT

The invention relates to novel pyridyl-2-oxy-phenyloxime derivatives of the formula ##STR1## wherein Q is an aliphatic or araliphatic ether or ester radical as defined in the specification, R 1  is hydrogen, halogen, or a cyano, nitro, lower alkyl or halomethyl group, R 2  is halogen, R 3  is hydrogen, the nitro or cyano group, n is 0, 1 or 2 and X is hydrogen, halogen or a member selected from the group consisting of cyano, nitro, lower alkyl, lower alkanoyl, carboxylic acid lower alkyl ester or carboxamide. These compounds have good selective herbicidal action, they inhibit plant growth, and they can be employed as safeners for protecting cultivated plants from the phytotoxic action of aggressive agrochemicals.

This is a divisional of application Ser. No. 172,575 filed on July 28,1980, now U.S. Pat. No. 4,322,241 issued Mar. 30, 1982.

The present invention relates to novel pyridyl-2-oxyphenyloximederivatives, processes for their production, herbicidal and plantgrowth-regulating compositions of which they are active ingredients, andtheir use as selective herbicides in crops of cultivated plants.

Pyridyloxy-phenoxyalkanecarboxylic acid derivatives which possessherbicidal and plant growth regulating properties are known from theprior art (e.g. German Offenlegungsschrift Nos. 2 546 251, 2 649 706 or2 732 846). Diphenyloximes having herbicidal properties have recentlybeen disclosed in Belgian patent 870 068. The oxime derivatives of thepresent invention are novel.

The pyridyl-2-oxy-phenyloxime derivatives have the formula I ##STR2##wherein R₁ is hydrogen, halogen or a cyano, nitro, lower alkyl orhalomethyl group, R₂ is halogen, R₃ is hydrogen, halogen, the nitro orcyano group, n is 0, 1 or 2, X is hydrogen, halogen or a member selectedfrom the groups consisting of cyano, nitro, lower alkyl, lower alkanoyl,carboxylic acid lower alkyl ester or carboxamide, Q is lower alkyl whichis straight-chain or branched or which can be interrupted by heteroatomsor substituted by halogen; lower alkenyl or haloalkenyl; lower alkynyl;C₃ -C₇ cycloalkyl which is unsubstituted or substituted by halogen;lower cyanoalkyl; a lower alkanecarboxylic acid ester group; a loweralkanecarboxylic acid amide group; an aliphatic acyl radical; anaraliphatic, cycloaliphatic or unsubstituted or substituted aromatic orheterocyclic acyl radical; an aliphatic, araliphatic, cycloaliphatic orunsubstituted or substituted aromatic or heterocyclic carbonic acidester radical; an alkylsulfonyl group; a sulfonamide group; a carbamoylradical.

By halogen in formula I is meant fluorine, chlorine, bromine or iodine.

The term "alkyl" by itself or as moiety of a substituent comprisesbranched or unbranched C₁ -C₈ alkyl groups. Lower alkyl denotes alkyl of1 to 4 carbon atoms, for example: methyl, ethyl, propyl, isopropyl,butyl, sec-butyl, tertbutyl, and the higher homologues amyl, isoamyl,hexyl, heptyl, octyl together with the isomers thereof. By analogy,cyanoalkyl contains one additional carbon atom and alkanecarboxylic acidester groups contain at least two additional carbon atoms.

Alkenyl radicals are aliphatic radicals containing one or also twodouble bonds (alkadienyls) and a maximum of 6, preferably 4, carbonatoms. Haloalkenyl radicals contain not more than 3 halogen atoms,preferably chlorine or bromine atoms. Alkynyl denotes propynyl(=propargyl) and butynyl.

Carboxamide groups comprise also monosubstituted or symmetrically orunsymmetrically disubstituted amides. The substituents can be selectedfrom the group consisting of lower alkyl, lower alkenyl, propynyl orbutynyl and also a phenyl ring which can be substituted orunsubstituted.

C₃ -C₇ Cycloalkyl groups are cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl and cycloheptyl. Cycloaliphatic radicals correspond to thesering systems, but, according to circumstances, can contain in additionone or more double bonds.

An araliphatic radical comprises an aryl group, such as unsubstituted ormono-, di- or trisubstituted phenyl, or also naphthyl, fluorenyl, orindanyl, which is bonded to the remainder of the molecule through loweralkyl or lower alkenyl. Examples are benzyl, phenethyl, phenylallyl andhomologues.

Aromatic carboxylic acids are derived from aromatics, especially phenyl,and can be substituted. Heterocyclic carboxylic acids are derived frommonocyclic or bicyclic rings containing 1 to 3 identical or differentheteroatoms O, S and N. Mention may be made of heterocyclic ring systemshaving 3 to 6, especially 5 or 6, members, which can be saturated,partially saturated or unsaturated, and can be substituted orunsubstituted. Without any limitation being implied, there may bementioned as examples: furane, nitrofurane, bromofurane, methylfurane,thiophene, chlorothiophene, pyridine, 2,6-dichloropyridine, pyrimidine,pyridazine, pyrazine, piperidine, methylpiperidine, morpholine,thiomorpholine, tetrahydrofurane, oxazole, pyrazole, pyrrole, pyrroline,pyrrolidine, thiazole, 2,3-dihydro-4H-pyrane, pyrane, dioxane,1,4-oxathi-(2)-ine.

Examples of aliphatic chains interrupted by heteroatoms are:methoxyethyl, ethoxyethyl, propoxyethyl, butoxyethyl, methoxypropyl,ethylthioethyl, methylaminoethyl, tert-butylaminoethyl,alkoxyalkoxyalkyl, such as methoxyethoxyethyl.

A carbamoyl radical (-CO-NH- or -CO-N<) carries at the nitrogen atom oneor two radicals selected from the group consisting of lower alkyl, loweralkoxyalkyl, lower alkenyl, lower haloalkenyl, alkynyl or a hydrogenatom, and alternatively a C₃ -C₆ cycloalkyl ring or else a phenyl ringwhich is unsubstituted, or, as in the case of R₂ /R₃, can besubstituted.

Preferred compounds of the formula I are those in which X is the methylor cyano group and Q is an ester radical ##STR3## wherein R is loweralkyl, R₄ is hydrogen or lower alkyl, R₅ is hydrogen, lower alkyl orlower alkoxy, and R₁ and R₂ are in the 3- and 5-position respectively ofthe pyridyl ring. In addition, R₁ is preferably chlorine ortrifluoromethyl, and R₂ is chlorine.

When employed in rates of application of 0.5 to 4 kg/ha and more, thepyridyl-2-oxy-phenyloxime derivatives of the formula I have a pronouncedherbicidal action against dicotyledonous weeds such as Sida, Sesbania,Amaranthus, Sinapis, Ipomoea, Galium, Pastinak, Rumex, Matricaria,Chrysanthemum, Abutilon, Solanum etc. However, when employed in higherrates of application of at least 2 to 4 kg/hectare, a number of thecompounds act on monocotyledonous weeds, such as Digitaria, Setaria andEchinochloa, whilst monocotyledonous cultivated plants, such as barley,wheat, maize, oats and rice, remain virtually undamaged at lower ratesof application and suffer only minor damage at higher rates.

With these compounds it has been possible to obtain good practicalresults in selectively controlling in particular dicotyledonous weeds incereals, maize and rice.

The active ingredients (compounds of the formula I) and compositionscontaining them can be employed as contact herbicides in pre-emergenceapplication to sown cultivated areas, but preferably in post-emergenceapplication to weed-infested crops of cultivated plants.

The compositions of the present invention are obtained in known mannerby intimately mixing and grinding active ingredients of the generalformula I with suitable carriers and/or dispersants, with or without theaddition of anti-foam agents, wetting agents, dispersants and/orsolvents which are inert to the active ingredients. The activeingredients can be processed to the following formulations:

solid formulations: dust, tracking powders, granules (coated granules,impregnated granules and homogeneous granules),

active ingredient concentrates which are dispersible in water: wettablepowders, pastes, emulsions, emulsifiable concentrates:

liquid formulations: solutions.

The compounds of the formula I are obtained by methods which are knownper se. In a first method, a 2-halopyridine of the formula II ##STR4##is reacted with a hydroxybenzaldehyde of the formula III ##STR5## in thepresence of a base, to give a pyridyl-2-oxybenzaldehyde of the formulaIV ##STR6## which is reduced with sodium borohydride (NaBH₄), or a mildreducing agent, to give the pyridyl-2-oxy-benzyl alcohol of the formulaV ##STR7## which is then converted with thionyl chloride, thionylbromide or phosphoroxy chloride or phosphoroxy bromide to thecorresponding pyridyl-2-oxy-benzyl chloride or bromide of the formula VI##STR8##

This latter compound is then reacted with potassium cyanide or sodiumcyanide to give the corresponding cyanomethyl compound of the formulaVII ##STR9## which in turn is reacted with isoamyl nitrite (C₅ H₁₁iso-ON═O), in the presence of sodium methylate (NaOC₂ H₅), to give thepyridyl-2-oxy-phenyl-nitrile oxime salt of the formula VIII ##STR10##

In the above formulae II to VIII, the symbols n, R₁, R₂ and R₃ are asdefined for formula I.

One process for the production of the pyridyl-2-oxy-phenyloximederivatives of the formula I, wherein X is cyano, comprises reacting anappropriately substituted pyridyl-2-oxy-phenyl-nitrile oxime salt of theformula VIII above, wherein R₁, R₂ and R₃ have the given meanings, in aninert organic solvent and in the presence of a base, with a compound ofthe formula IX

    Y-Q                                                        (IX)

wherein Y is a halogen atom or a removable acid radical and Q has thegiven meaning.

A further method of obtaining the pyridyl-2-oxy-phenyloxime derivativesof the formula I consists in reacting the 2 -halopyridine of the formulaII with a benzaldehyde or phenyl ketone which is appropriatelysubstituted by R₃, in an inert organic solvent and in the presence of abase, to give either the pyridyl-2-oxy-benzaldehyde of the formula IV ora corresponding pyridyl-2-oxy-phenylketone of the formula X ##STR11##

Reaction of the compound of the formula X with hydroxylamine (H₂ NOH)yields a pyridyl-2-oxy-phenyloxime of the formula XI ##STR12## whereinX' is hydrogen or lower alkyl. In the formulae X and XI above, n, R₁, R₂and R₃ are as defined for formula I.

A further process for the production of the pyridyl-2-oxyphenyloximederivatives of the formula I comprises reacting apyridyl-2-oxy-phenyloxime of the formula XI above, wherein X' ishydrogen or lower alkyl, and n, R₁, R₂ and R₃ have the given meanings,in an inert organic solvent and in the presence of a base, with acompound of the formula IX, wherein Y is a halogen atom or a removableacid radical and Q has the given meanings, and, if desired, in compoundsof the formula I in which X is hydrogen, with appropriate reagentsreplacing the hydrogen atom by other radicals which fall within thedefinition of X.

The above reactions are carried out in the temperature range between 0°and 150° C. and in suitable solvents such as acetone, methyl ethylketone, acetonitrile, dimethyl formamide, or dimethyl sulfoxide.

Suitable bases are both inorganic bases such as alkali metal hydroxides,carbonates and bicarbonates of alkali metals and alkaline earth metals,and also dry ammonia, as well as organic bases, e.g. tertiary loweralkylamines such as triethylamine, trimethylamine, or also cyclicamines, e.g. pyridine, collidine, or also aromatic amines such asdimethyl aniline.

Examples of removable acid radicals Y are e.g. an alkylsulfonyl group,an arylsulfonyl group, a nitro group, or a halogenated fatty acidradical, e.g. the radical of trichloroacetic acid.

These and other condensation reactions of α-oximino compounds and thealkali metal salts thereof with reactants Y-Q are described in "OrganicReactions", 1953, Vol. 7, pp. 343 and 373.

Oximes always exist in two stereoisomeric forms, the synform andanti-form. Throughout this specification, both stereoisomeric formsshall be understood as existing individually and as mixtures in anyratio.

The following Examples describe the production of a number of compounds(active ingredients) of the formula I. Pressures are in millibars andparts and percentages are by weight.

EXAMPLE 1: Production of4-(3',5'-dichloropyridyl-2-oxy)-phenylgloxynitrile2-oxime-methylcarbonyl-eth-1"-yl) ether ##STR13##

(a) A mixture of 61 g of p-hydroxybenzaldehyde, 81.2 g of2,3,5-trichloropyridine, 35 g of pulverised potassium hydroxide and 300ml of dimethyl sulfoxide is stirred in a three-necked flask for 12 hoursat 150° C. After cooling, the reaction mixture is poured into anice-water mixture and extracted with ethyl acetate. The ethyl acetatesolution is dried over sodium sulfate and concentrated in vacuo,affording 112 g of 4-(3',5'-dichloropyridyl-2-oxy)-benzaldehyde with amelting point of 78° C.

(b) 13.4 g of 4-(3',5'-dichloropyridyl-2'-oxy)-benzaldehyde aredissolved in 80 ml of methanol and to the solution are added 2 g ofsodium borohydride at a temperature between 25° and 30° C. When thereaction is complete, the reaction mixture is stirred for 2 hours atroom temperature, then poured into water and extracted with ethylacetate. The organic phase is dried over sodium sulfate andconcentrated, affording 12.1 g of 4-(3',5'-dichloropyridyl-2-oxy)-benzylalcohol in the form of an oily product with a refractive index of n_(D)²⁴ 1.6133.

(c) 11.3 g of 4-(3',5'-dichloropyridyl-2'-oxy)-benzyl alcohol aredissolved in 50 ml of toluene and to this solution are added dropwise 5ml of thionyl chloride at room temperature. When the evolution of gashas ceased, the reaction mixture is heated for 2 hours at 100° C. Thereaction mixture is concentrated affording 8 g of4-(3',5'-pyridyl-2'-oxy)-benzyl chloride in the form of a solid productwith a melting point of 73°-75° C.

(d) A mixture of 26 g of 4-(3',5'-dichloropyridyl-2'-oxy)-benzylchloride, 6.5 g of potassium cyanide and 50 ml of acetonitrile arerefluxed for 20 hours. After cooling, the reaction mixture is pouredinto water. The crystalline precipitate is filtered with suction, washedwith water and dried, affording 24.5 g of4-(3',5'-dichloropyridyl-2'-oxy)-benzyl cyanide with a melting point of107°-108° C.

(e) With stirring, 6 g of sodium ethylate are dissolved in 80 ml ofabsolute alcohol in a three-necked flask and the solution is cooled to0° C. At this temperature, 24.2 g of4-(2',5'-dichloropyridyl-2'-oxy)-benzyl cyanide are added initially,followed by the dropwise addition of 11.6 ml of isopentyl nitrite atroom temperature. The reaction temperature is then stirred for 24 hoursat room temperature and the product is precipitated with 200 ml ofpetroleum ether. The precipitate is collected by filtration, washed withpetroleum ether and dried, affording 16.2 g of the sodium salt of4-(3',5'-dichloropyridyl-2'-oxy)-phenylglyoxylonitrile 2-oxime with amelting point above 280° C.

(f) In a three-necked flask, 12.1 g of the sodium salt of4-(3',5'-dichloropyridyl-2'-oxy)-phenylglyoxylonitrile-2-oxime aredissolved in 50 ml of dimethyl formamide. Then 4.2 ml of methyl2-bromopropionate are added dropwise. The reaction mixture is stirredovernight at room temperature, then poured into water and extracted withether. The ethereal extract is dried and concentrated, affording 12.7 gof the title compound in the form of a brown oil with a refractive indexof n_(D) ²³ 1.5855. (Compound 8).

EXAMPLE 2: Production of4-(3',5'-dichloropyridyl-2'-oxy)acetophenyloxime-(methoxycarbonyl-eth-1"-yl)ether ##STR14##

(a) 27 g of 4-(3',5'-dichloropyridyl-2'-oxy)-acetophenone (obtained byreaction of 2,3,5-trichloropyridine with para-hydroxyacetophenone) aredissolved in 150 ml of alcohol and, after addition of 100 ml of water,6.6. g of hydroxylamine hydrochloride and 9 g of sodium acetate, themixture is stirred for 4 hours at a bath temperature of 100° C. Aftercooling, the precipitated crystalline product is collected by filtrationand recrystallised from alcohol, affording 21 g of4-(3',5'-dichloropyridyl-2'-oxy)-acetophenyloxime with a melting pointof 118°-119° C.

(b) 15 g of the oxime obtained in (a) are dissolved in a solution of 70ml of methanol and 1.2 g of sodium and this solution is evaporated todryness in vacuo. The salt obtained is dissolved in dimethyl formamideand then 8.5 g of methyl 2-bromopropionate are added dropwise at roomtemperature. The reaction mixture is stirred for 12 hours, then pouredinto water and extracted with ethyl acetate. The solution is dried oversodium sulfate and concentrated in vacuo, affording 19 g of the titlecompound in the form of an oil with a refractive index of n_(D) ²³1.5734 (compound 1).

The following compounds are obtained by methods analogous to thosedescribed in the foregoing Examples.

                  TABLE 1                                                         ______________________________________                                         ##STR15##                                                                                                               Phys-                                                                         ical                               Com-                                       data                               pound R.sub.1 R.sub.2                                                                             R.sub.3                                                                           X    Q             (°C.)                       ______________________________________                                        1     Cl      Cl    H   CH.sub.3                                                                           CH(CH.sub.3)COOCH.sub.3                                                                     n.sub.D.sup.23                                                                1.5734                             2     Cl      Cl    H   CH.sub.3                                                                           CONHCH.sub.3  resin                              3     Cl      Cl    H   CH.sub.3                                                                           CONHC.sub.6 H.sub.5                                                                         m.p.                                                                          113°                        4     Cl      Cl    H   CH.sub.3                                                                           CONHC.sub.6 H.sub.3 (3,4-Cl)                                                                resin                              5     Cl      Cl    H   CH.sub.3                                                                           COC.sub.6 H.sub.5                                                                           m.p.                                                                          114°                        6     Cl      Cl    H   CH.sub.3                                                                           CH.sub.2 CN   n.sub.D.sup.23                                                                1.5788                             7     Cl      Cl    H   CH.sub.3                                                                           COCH.sub.3    m.p.                                                                          115-6°                      8     Cl      Cl    H   CN   CH(CH.sub.3)COOCH.sub.3                                                                     n.sub.D.sup.23                                                                1.5855                             9     CF.sub.3                                                                              Cl    H   CN   CH(CH.sub.3)COOCH.sub.3                                                                     n.sub.D.sup.30                                                                1.5354                             10    CF.sub.3                                                                              Cl    H   CN   CH(CH.sub.3)COOC.sub.2 H.sub.5                   11    CF.sub.3                                                                              Cl    H   CN   CH(CH.sub.3)CN                                   12    CF.sub.3                                                                              Cl    H   CN   CH(CH.sub.3)COOC.sub.3 H.sub.7 iso               13    CF.sub.3                                                                              Cl    H   CN   CH(CH.sub.3)COOC.sub.3 H.sub.7 n                 14    CF.sub.3                                                                              Cl    H   CN   CH(CH.sub.3)COOC.sub.4 H.sub.9 iso                                                          n.sub.D.sup.30                                                                1.5136                             15    CF.sub.3                                                                              Cl    H   CN   CONHCH.sub.3                                     16    CF.sub.3                                                                              Cl    H   CN   CONHC.sub.6 H.sub.5                              17    CF.sub.3                                                                              Cl    H   CN   COCH.sub.3                                       18    CF.sub.3                                                                              Cl    H   CN   COC.sub.6 H.sub.4 (4'Cl)                         19    CF.sub.3                                                                              Cl    H   CN   CO(CH.sub.3)COOC.sub.4 H.sub.9 n                 20    CF.sub.3                                                                              H     H   CN   CH(CH.sub.3)COOCH.sub.3                          21    CClF.sub.2                                                                            Cl    H   CN   CH(CH.sub.3)COOCH.sub.3                          ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                         ##STR16##                                                                    Com-                                      Physical                            pound R.sub.1 R.sub.2                                                                             R.sub.3                                                                            X    Q           data                                ______________________________________                                        1     Cl      Cl    Cl   CN   CH(CH.sub.3)COOCH.sub.3                         2     CF.sub.3                                                                              Cl    Cl   CN   CH(CH.sub.3)COOCH.sub.3                         3     Cl      Cl    H    CH.sub.3                                                                           CH(CH.sub.3)COOCH.sub.3                                                                   n.sub.D.sup.24                                                                1.5759                              4     CF.sub.3                                                                              Cl    Cl   CH.sub.3                                                                           CH(CH.sub.3)COOCH.sub.3                         5     Cl      Cl    Cl   CH.sub.3                                                                           COCH.sub.3                                      6     CF.sub.3                                                                              Cl    Cl   CH.sub.3                                                                           COCH.sub.3                                      7     Cl      Cl    Cl   CH.sub.3                                                                           COC.sub.6 H.sub.5                               8     CF.sub.3                                                                              Cl    Cl   CH.sub.3                                                                           COC.sub.6 H.sub.5                               9     Cl      Cl    Cl   CH.sub.3                                                                           CONHCH.sub.3                                    10    CF.sub.3                                                                              Cl    Cl   CH.sub.3                                                                           CONHCH.sub.3                                    11    Cl      Cl    Cl   CH.sub.3                                                                           CONHC.sub.6 H.sub.5                             12    Cl      Cl    Cl   CH.sub.3                                                                           CONHC.sub.6 H.sub.5                             13    Cl      Cl    NO.sub.2                                                                           CH.sub.3                                                                           COOCH.sub.3                                     ______________________________________                                    

Example 14

Production of ready-for-use solid and liquid formulations and activeingredient concentrates. Throughout, parts and percentages are byweight.

Granules

The following substances are used to formulate 5% granules:

5 parts of4-(3',5'-dichloropyridyl-2'-oxy)-acetophenoxime-(methoxycarbonyl)-eth-1"-yl)ether

0.25 parts of epoxidised vegetable oil

0.25 parts of cetyl polyglycol ether,

3.50 parts of polyethylene glycol,

91 parts of kaolin (particle size 0.3-0.8 mm).

The active ingredient is mixed with epoxidised vegetable oil dissolvedwith 6 parts of acetone, and the polyethylene glycol and cetylpolyglycol ether are then added. The resultant solution is sprayed onkaolin and subsequently evaporated in vacuo.

Wettable Powder

The following constituents are used to formulate

(a) a 70% and (b) a 10% wettable powder:

(a)

70 parts of4-(3',5'-dichloropyridyl-2-oxy)-phenylglyoxalonitrile-2-oxime-methyl-eth-1"-yl)ether,

5 parts of sodium dibutylnaphthylsulfonate,

3 parts of naphthalenesulfonic acid/phenolsulfonic acid/formaldehydecondensate (3:2:1),

10 parts of kaolin,

12 parts of Champagne chalk;

(b)

10 parts of the above active ingredient,

3 parts of a mixture of the sodium salts of saturated fatty alcoholsulfates,

5 parts of naphthalenesulfonic acid/formaldehyde condensate,

83 parts of kaolin.

The respective active ingredient is applied to the correspondingcarriers (kaolin and chalk) and then these are mixed and ground, toyield wettable powders of excellent wettability and suspension powder.By diluting these wettable powders with water it is possible to obtainsuspensions containing 0.1 to 80% of active ingredient. Thesesuspensions are suitable for controlling weeds in cultivations ofplants.

Paste

The following substances are used to formulate a 45% paste:

45 parts of4-(3',5'-dichloropyridyl-2'-oxy)-phenylglyoxylonitrile-2-oxime-methylcarbonyl-eth-1"-yl)ether,

5 parts of sodium aluminium silicate,

14 parts of cetyl polyglycol ether with 8 moles of ethylene oxide,

1 part of oleyl polyglycol ether with 5 moles of ethylene oxide,

2 parts of spindle oil,

10 parts of polyethylene glycol,

23 parts of water.

The active ingredient is intimately mixed with the additives inappropriate devices and ground. By diluting the resultant paste withwater, it is possible to prepare suspensions of the desiredconcentration.

Emulsifiable Concentrate

The following ingredients are mixed to formulate a 25% emulsionconcentrate:

25 parts of4-(3',5'-dichloropyridyl-2'-oxy)-acetophenyloxime-(methoxycarbonyl-eth-1"-yl)ether,

5 parts of a mixture of nonylphenolpolyoxyethylene and calciumdodecylbenzenesulfonate,

15 parts of cyclohexanone,

55 parts of xylene.

This concentrate can be diluted with water to give emulsions in suitableconcentrations of e.g. 0.1 to 10%.

Example 4

The following test methods are employed to establish the usefulness ofthe compounds of the formula I as pre-emergence and post-emergenceherbicides.

Pre-emergence Herbicidal Action (Inhibition of Germination)

In a greenhouse, immediately after sowing the test plants in seeddishes, the surface of the soil is treated with an aqueous dispersion ofthe active ingredients, obtained from a 25% emulsifiable concentrate orfrom a 25% wettable powder with active ingredients which, on account oftheir insufficient solubility, cannot be formulated to an emulsifiableconcentrate. Four different concentration series were used,corresponding to 4, 2, 1 and 0.5 kg of active ingredient per hectarerespectively. The seed dishes are kept in the greenhouse at 22°-25° C.and 50-70% relative humidity, and the test is evaluated 3 weeks later.Compounds 8, 9 and 14 of Table 1 were most effective, especially againstdicotyledonous plants in rates of application of 0.5 kg/ha.

Post-emergence Herbicidal Action (Contact Herbicide)

A large number of weeds and cultivated plants, both mono- anddicotyledonous, are sprayed post-emergence in the 4- to 6-leaf stagewith an aqueous active ingredient dispersion in rates of 0.125, 0.25 and0.5 kg of active ingredient per hectare and kept at 24° C.-26° C. and45-60% relative humidity. The test is evaluated at least 15 days aftertreatment. Compounds 8, 9 and 14 of Table 1 were most effective,especially against dicotyledonous plants at a rate of application of 0.5kg/ha.

What is claimed is:
 1. A compound of the formula ##STR17## wherein R₁ ishalogen or trifluoromethyl,X is methyl or cyano, and Q is lowercyanoalkyl.
 2. 5-(3,5-Dichloropyridyl-2-oxy)-acetophenyloximecyanomethyl ether according to claim
 1. 3. A method of selectivelycontrolling weeds in crops of cultivated plants, which comprisesapplying to said crops a herbicidally effective amount of a compound ofclaim
 1. 4. A herbicidal composition which contains (1) as activeingredient a herbicidally effective amount of a compound according toclaim 1 and (2) an inert carrier.